Method for enhancing ultrasonic pretreatment of municipal sludge

Abstract

The invention discloses a method for enhancing ultrasonic pretreatment of municipal sludge, comprising the steps of dissolving enough micron bubbles in water under high pressure environment to obtainmicron bubble water with a bubble particle size of 1 to 40 microns; mixing the micron bubble water with a sludge liquid to enable the bubbles to be evenly dispersed inside sludge; enabling the sludgeliquid to enter a reaction unit of a sealed environment, and conducting quick pressurization on the external environment of the sludge; when the pressure intensity reaches 2 MPa, turning on an ultrasonic device, and conducting ultrasonic treatment on sludge particles, so as to efficiently realize cell breaking dissolution of cellular organic matter; and during the ultrasonic treatment process, continuously stirring the sludge, and maintaining the external pressurized environment of the sludge at 2 MPa. According to the invention, micron bubbles and pressurized environment are introduced in theprocess of sludge ultrasonic cell breaking dissolution, the cell breaking dissolution process of sludge particles is greatly enhanced, an important green technical solution is provided for urban sludge pretreatment, and significant social benefits and environment benefits are achieved.

Description

Technical field [0001] The invention relates to the technical field of sewage sludge treatment, in particular to a method for strengthening ultrasonic pretreatment of urban sludge. Background technique [0002] With the popularization and application of the activated sludge method to treat domestic sewage, the output of surplus sludge has increased sharply. The output of sludge has reached 43 million tons / year (calculated with a moisture content of 80%), and the situation of surplus sludge treatment and disposal has become increasingly severe. Ultrasonic pretreatment of sludge is an effective method to promote the decomposition of sludge, with fast decomposition speed and wide application range. The main method of ultrasonic cracking of sludge is the cavitation effect, and the resulting thermal and chemical effects. Cavitation is more likely to occur in the frequency range of 20-40kHz, and low-frequency 41kHz ultrasound is the most effective for sludge decomposition. The ultras...

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Problems solved by technology

However, this patent does not take into account that the bubbles in the water will float into the air after a period of ultrasonication, and the heating of the water body will also reduce the solubility of the gas in the water, and the nanobubbles cannot exist in the water for a long time, resulting in a reduction in processing efficiency; the nanobubbles are prepared with combustible biogas , did not take into account that a large amount of ammonia, hydrogen sulfide and other gases in the biogas dissolve and accumulate in water, which is not conducive to the subsequent anaerobic digestion, and is not suitable for ultrasonic pretreatment of municipal sludge

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